Hi Folks:
A coworker just showed me his serpentine belt, in his hands. It ‘blew off’. It’s in good shape, and the pulleys turn freely, but honestly, it looks to me that his crank pulley is sticking out about a half-inch too far, compared to the other pulleys. By hand, it didn’t feel loose. Ever hear of such a thing?
it’s a 2001 XJ automatic.
Thanks!
HarryHydro

 

yes a pulley can come loose from the hub if the pulley is mounted as a damper with rubber between it and the hub. If loose, the pulley may then walk off the hub.

Only fix is replacement.

 

Very common problem. The crank pulley is also called the harmonic balancer. There is a rubber section between the outer ring and the center hub. When it dryrots over time and fails, the outer ring can start wobbling, or start walking forward or backwards. This usually results in throwing the belt when it walks outward, or rubbing on the timing cover if it walks inwards.

There are numerous writeups and videos out there for pulling and replacing it. I recommend replacing the crank seal behind it at the same time. My usual advice for installing the new one is to get a longer crank bolt, washer and nut. Thread the longer bolt all the way in and use the nut/washer to pull the new balancer on. DO NOT use the original bolt to do this. It's too short and will only engage a few threads at first, and you risk ripping the first couple of threads out of the end of the crankshaft.

 

 

. Mine wore a small hole in the timing chain on a 89

 

cover, you mean?

 

sorry ,TIMING CHAIN COVER